The present invention relates to a portable computer which comprises a keyboard and in which a coordinate input device and a display device are integrally formed as one body. More specifically, the present invention relates to a computer system comprising a means for inhibiting an input operation from the keyboard when necessary.
The personal computers recently developed include small-sized computers which are light in weight and improved in portability. Normally, such small-sized computers comprise not only a keyboard but also other types of data input devices, such as a pointing device (e.g., a mouse) and a tablet-type input device.
The tablet-type input device comprises a liquid crystal display (LCD) normally used as a display device, and a tablet assembled integrally with the liquid crystal display. Data are entered from the tablet-type input device by moving a pen or the like on the screen of the LCD. The tablet-type input device is advantageous in many respects. For example, a character or letter written on the screen with the pen can be recognized and entered as text data.
Even a computer comprising a tablet-type input device is provided with a keyboard (which is a standard type data input device). Therefore, the user can selectively use either the tablet-type input device or the keyboard, depending upon the circumstances. For example, the user will use the tablet-type input device when a character string should be entered with the pen to make notes of a something, and will use the keyboard when instructions of application software program should be entered.
As mentioned above, a small-sized computer employs not only a keyboard but also a tablet-type input device, for entering data. In general, a small-sized computer, particularly a portable computer, is designed in such a manner that it can be used not only on a steady desk but also in a train or a room where there is no desk or table. This being so, when the user enters data from the tablet-type input device by use of a pen, it is likely that the user's hand will touch the keys of the keyboard, resulting in undesirable data entry. Even when the tablet-type input device is not in use, there is still a problem that has to be solved. That is, when the user is temporarily away from the computer, another person may operate the computer mistakenly or maliciously, and no measure is taken in the prior art to cope with this situation. In conclusion, it is a common occurrence that wrong or undesirable data will be entered due to the improper use of the keyboard. This is one of the factors underlying the undesirable operation of the computer.